Detect Network Share Connection Removal in Microsoft Sentinel
Adversaries remove Windows network share connections after use to clean up traces of lateral movement and data access. Network shares mapped via net use or UNC paths leave artifacts in the Windows registry (HKCU\Network), Windows event logs (Event ID 5140 — network share object accessed, Event ID 5142 — network share created), and in the MRU list. The primary utility for removal is net use \\target\share /delete or net use * /DELETE /Y to remove all mapped drives simultaneously. RobbinHood ransomware used net use * /DELETE /Y to disconnect all network shares before encryption, likely to ensure local encryption of any mapped network paths. Threat Group-3390 detached network shares after exfiltrating files. InvisiMole, DUSTTRAP (APT41), and various ransomware families routinely perform share cleanup as a post-exploitation step.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1070 Indicator Removal
- Sub-technique
- T1070.005 Network Share Connection Removal
- Canonical reference
- https://attack.mitre.org/techniques/T1070/005/
KQL Detection Query
DeviceProcessEvents
| where Timestamp > ago(24h)
| where FileName =~ "net.exe" or FileName =~ "net1.exe"
| where ProcessCommandLine has "use" and ProcessCommandLine has_any ("/delete", "/DELETE", "/d")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine,
InitiatingProcessFileName, InitiatingProcessCommandLine
| sort by Timestamp desc
| union (
DeviceProcessEvents
| where Timestamp > ago(24h)
| where FileName =~ "net.exe" or FileName =~ "net1.exe"
| where ProcessCommandLine has "use" and ProcessCommandLine has "*"
| project Timestamp, DeviceName, AccountName, ProcessCommandLine,
InitiatingProcessFileName, InitiatingProcessCommandLine
)
| sort by Timestamp descDetects network share removal commands using net.exe and net1.exe with the /delete flag. Captures both targeted share removal (net use \\server\share /delete) and bulk removal of all mapped drives (net use * /DELETE /Y). The net1.exe variant is included because Windows sometimes executes net1.exe as a child process when net.exe is called. High-severity when * /DELETE is used, indicating bulk cleanup typical of ransomware pre-encryption or post-exfiltration cleanup.
Data Sources
Required Tables
False Positives & Tuning
- IT administrators running scripts that map and then unmap network shares as part of batch file operations
- Logoff scripts configured in Group Policy that disconnect mapped drives when users log off
- VPN clients that disconnect network shares when the VPN session ends and reconnect when it re-establishes
- Backup agents that map network backup destinations, perform backup, then disconnect
Other platforms for T1070.005
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Remove Specific Network Share Connection with net use /delete
Expected signal: Sysmon EventCode 1: net.exe process creation with 'use \\127.0.0.1\IPC$ /delete' command line. Windows Security Event ID 5140 (share accessed) and then no corresponding 5142 (share removed) since the share never fully established due to authentication. MDE DeviceProcessEvents captures both the mapping and deletion commands.
- Test 2Bulk Network Share Removal with net use * /DELETE
Expected signal: Sysmon EventCode 1: net.exe with '* /DELETE /Y' in command line. Windows Security Event ID 5140 may fire for each share that was disconnected. The wildcard (*) in the command line is a high-fidelity indicator of bulk share removal. MDE DeviceProcessEvents captures the full command including the * wildcard.
- Test 3Delete Network Share Registry History (MountPoints2 Cleanup)
Expected signal: reg.exe process creation with 'delete' and 'MountPoints2' in command line. Sysmon EventCode 12 (RegistryKeyDeleted) for HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2. Security Event ID 4657 if registry auditing is enabled for HKCU keys.
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